// // 級数\(\displaystyle \sum^{\infty}_{n=1} \frac{1}{n}\)の和から\(n\)に\(0\)の文字が入った項，例えば，\(\displaystyle \frac{1}{10}\)，\(\displaystyle \frac{1}{20}\)，\(\cdots \)，\(\displaystyle \frac{1}{100}\)，\(\displaystyle \frac{1}…